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3 years ago

How are petrified fossils similar to preserved remains? How are they different?

2 answers:

8 0

Well, both fossils and preserved remains retain the shape and form of the remains, but fossils do not actually retain the matter that made up the remains, instead, bones and tissues (usually just bones) have been replaced with stone.

konstantin123 [22]3 years ago

4 0

You might be interested in

Nitrogen and hydrogen combine to form ammonia in the Haber process.

Vaselesa [24]

Answer:

-105 kJ

Explanation:

The enthalpy change of a reaction is the sum of the energy of the bonds of the reactants and the products. The bonds at the reactants are being broken, so it's an endothermic reaction, so the bond energy must be positive.

The bonds at the products are being formed, so the process is exothermic, and the bond energy must be negative. There are being broken 1 N≡N bond and 3 H-H bonds, and are being formed 6 N-H bonds:

Reactants: 945 + 3*432 = 2241 kJ

Products: 6*(-391) = -2346 kJ

ΔH = 2241 - 2346

ΔH = -105 kJ

8 0

3 years ago

Elements of modern periodic table are arrang in ---Group 2A elements are called ------ and group 7A element table are called....

pentagon [3]

Answer:

c) atomic number / alkaline earth metals/ and halogens

Explanation:

Elements of modern periodic table are arrang in atomic number; for its electron configuration and its chemical properties. This arrangement shows periodic trends.

Alkaline earth metals are a group of elements that are located in group 2 of the Periodic Table and are the following: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba) and Radio (Ra).

The Halogens are the chemical elements that form group 17 (XVII A, previously used) or group VII A of the periodic table: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and teneso (Ts)

8 0

3 years ago

Write a balanced equation and determine Eº for each of the following cells: a) Cr Cr3+||Ni2+|Ni b) (CF|C1,||MnO | Mn?)

Alexxx [7]

Answer:

Explanation:

Step 1: Write both half reactions

Cr / Cr3+ : oxidation Cr(s) → Cr3+ + 3e-

Ni2+ / Ni : reduction Ni2+ +2e- → Ni

Step 2: Balance reactions and look up the standard potential for the half-reactions

2(Cr → Cr3+ + 3e-) E° ox = 0.74 V

3(Ni2+ +2e- → Ni) E° red = -0.25 V

2Cr + 3Ni2+ +6e- → 2Cr3+ +6e- + 3Ni

E°cell = E° red + E° ox = -0.25 + 0.74 = 0.49

E = E ° − 0.0257 V /n * ln Q = E ° − 0.0257 V /n *l n [ C r 3 + ]/ [ N i 2 + ]

With E° = 0.49 V

Step 1: Write both half reactions

MnO4-/ Mn2+ (redution) MnO4- +8H+ +5e- ⇔ Mn2+ +4H2O

Cf ⇔ Cf2+ +2e- (oxidation) Cf ⇔ Cf2+ +2e-

Step 2: Balance reactions and look up the standard potential for the half-reactions

MnO4- +8H+ +10-e- ⇔ Mn2+ +4H2O E° = 1.51 V

5Cf ⇔ 5 Cf2+ +10e- E° =2.12 V

2 MnO4- + 16H+ + 5Cf ⇔ 2Mn2+ + 8H2O + 5Cf2+

E°cell = E° red + E° ox = 1.51 + 2.12 = 3.63 V

E = E ° − 0.0257 V /n * ln Q = E ° − 0.0257 V /n *l n [ C f2 + ]/ [ Mno4- ]

With E° =3.63 V

7 0

3 years ago

The ____ particles of an atom which are called electrons

blsea [12.9K]

Answer:

Subatomic particles

Explanation:

I hope it helped

5 0

3 years ago

Answer ASAP 25 points

kykrilka [37]

<u>Answer:</u> The correct answer is $NH_3$ is the base and $NH_4Cl$ is the salt.

<u>Explanation:</u>

Neutralization reaction is defined as the reaction in which an acid reacts with a base to produce salt and water as products.

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and a base is defined as a substance which accepts protons.

For the given chemical reaction:

$NH_3+HCl\rightarrow NH_4Cl$

Here, $NH_3$ is a base because it is accepting proton and HCl is an acid because it is loosing proton.

$NH_4Cl$ is considered as a salt because it is formed by the combination of acid and base.

Hence, the correct answer is $NH_3$ is the base and $NH_4Cl$ is the salt.

8 0

3 years ago

Read 2 more answers